In hermetic refrigerant compressor units, oil is drawn from a sump by a lubrication pump to provide lubrication to the compressor. It is well known that if the oil in the sump is caused to froth or foam, that there is a reduction in the sound of the unit. Accordingly, an impeller, generally in the form of paddles, has been placed on the lubricant pickup tube for foam generation, thus reducing noise of the unit. However, in every rotating body of fluid there is a centrifugal pressure gradient which balances the centripetal acceleration of the fluid. If the fluid has two components, one less dense than the other, the less dense fluid will be forced towards the center of rotation while the more dense fluid will be forced towards the outside. For example, when the oil of a compressor is caused to foam by an impeller, any refrigerant bubbles that are trapped in the oil tend to accumulate at the center of the impeller. Thus, the presence of paddles has reduced the amount of oil pumped and, on occasion, there may be a compressor failure due to inadequate lubrication. The apparent cause of inadequate lubrication is the accumulation of refrigerant vapor near the pump inlet which inhibits the flow of oil into the end of the pickup tube so that oil is no longer supplied to the bearings.